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.TH EXPORTFS 4

.SH NAME

exportfs, srvfs \- network file server plumbing

.SH SYNOPSIS

.B exportfs

[

.I options

]

.PP

.B srvfs

[

.B -dR

]

[

.B -p

.I perm

]

[

.B -P

.I patternfile

] [

.B -e

.I exportprog

]

.I name

.I path

.SH DESCRIPTION

.I Exportfs

is a user level file server that allows Plan 9 compute servers, rather

than file servers, to export portions of a name space across networks.

The service is started either by the

.IR cpu (1)

command or by a network listener process.  An initial protocol

establishes a root directory for the exported name space.

The

connection to

.I exportfs

is then mounted, typically on

.BR /mnt/term .

.I Exportfs

then acts as a relay file server: operations in the imported file

tree are executed on the remote server and the results returned.  This

gives the appearance of exporting a name space from a remote machine

into a local file tree.

.PP

The options are:

.TF "-A \fIaddress"

.PD

.TP

.B -A \fIaddress

Use the network

.I address

to announce

.IR aan (8)

connections,

if requested by the initial protocol.

.TP

.B -a

Authenticate the user with the

.I p9any

protocol before running the regular

.I exportfs

session; used when 

.I exportfs

is invoked to handle an incoming network connection.

.I Exportfs

creates a new name space for each connection, using

.B /lib/namespace

by default (see

.IR namespace (6)).

.TP

.B -B \fIaddress

Dial

.IR address ,

authenticate as a

.I p9any

client, and then

serve that network connection.

Requires setting the root of the name space with 

.B -r

or

.BR -s .

The remote system should run

.B import

.B -B

to handle the call.

See

.IR import (4)

for an example.

.TP

.B -d -f \fIdbgfile

Log all 9P traffic to

.I dbgfile

(default

.BR /tmp/exportdb ).

.TP

.B -e '\fIenc auth\fL'

Set the encryption and authentication algorithms to use for

encrypting the wire traffic (see

.IR ssl (3)).

The defaults are

.B rc4_256

and

.BR sha1 .

.TP

.B -m \fImsize

Set the maximum message size that 

.I exportfs

should offer to send (see

.IR version (5));

this helps tunneled

9P connections to avoid unnecessary fragmentation.

.TP

.B -N \fInsfile

Serve the name space described by

.IR nsfile .

.TP

.B -n

Disallow mounts by user

.BR none .

.TP

.B -P \fIpatternfile

Restrict the set of exported files.

.I Patternfile

contains one regular expression per line,

to be matched against path names

relative to the current working directory

and starting with

.BR ./ .

For a file to be exported, all lines with a prefix

.B +

must match and all those with prefix

.B -

must not match.

.TP

.B -R

Make the served name space read only.

.TP

.B -r \fIroot

Bypass the initial protocol, serving the name space rooted at

.IR root .

A corresponding

.IR import (4)

must use the

.B -m

option.

.TP

.B -S \fIservice

Bypass the initial protocol, serving the result of mounting

.IR service .

A separate mount is used for each

.IR attach (5)

message,

to correctly handle servers in which each mount

corresponds to a different client

(e.g.,

.IR rio (4)).

A corresponding

.IR import (4)

must use the

.B -m

option.

.TP

.B -s

equivalent to

.B -r

.BR / ;

kept for compatibility.

.PD

.PP

The

.B cpu

command uses

.I exportfs

to serve device files in the terminal.  The

.IR import (4)

command calls

.I exportfs

on a remote machine, permitting users to access arbitrary pieces of

name space on other systems.

.PP

Because the kernel disallows reads and writes on mounted pipes

(as might be found in

.BR /srv ),

.I exportfs

calls itself (with appropriate

.B -m

and

.B -S 

options) to simulate reads and writes on such files.

.PP

.I Srvfs

invokes

.I exportprog

(default

.BR /bin/exportfs )

to create a mountable file system from a name space

and posts it at

.BI /srv/ name ,

which is created with mode

.I perm

(default 0600).

The name space is the directory tree rooted at 

.IR path .

The

.BR -d ,

.BR -P ,

and

.B -R

options, if present, are relayed to

.IR exportprog .

.SH EXAMPLES

To export the archive of one user for one month, except for secrets,

.IP

.EX

cd /n/dump

echo '+ ^\e.(/2003(/10..(/usr(/glenda/?)?)?)?)?' > /tmp/pattern

echo '- \e.(aes|pgp)$' >> /tmp/pattern

exportfs -P /tmp/pattern

.EE

.LP

Use

.I srvfs

to enable mounting of an FTP file system (see

.IR ftpfs (4))

in several windows, 

or to publish a

.B /proc

(see

.IR proc (3))

with a broken process so a remote person may debug the program:

.IP

.EX

srvfs ftp /n/ftp

srvfs broke /mnt/term/proc

.EE

.LP

Use 

.I srvfs

to obtain a copy of a service to be manipulated directly

by a user program like

.IR nfsserver (8):

.IP

.EX

srvfs nfs.boot /srv/boot

aux/nfsserver -f /srv/nfs.boot

.EE

.LP

Use

.I srvfs

to spy on all accesses to a particular subtree:

.IP

.EX

srvfs -d spy /

tail -f /tmp/exportdb &

mount /srv/spy /n/spy

cd /n/spy; ls

.EE

.SH SOURCE

.B /sys/src/cmd/exportfs

.br

.B /sys/src/cmd/srvfs.c

.SH SEE ALSO

.IR dial (2),

.IR import (4),

.IR aan (8),

.IR listen (8)